Systematics and Evolution (HA)

Lantana (Lantana spp.) as Environmental Weeds (TRIN - CERF Project)

Commonwealth Environment Research Facilites (CERF)

Lantana (Lantana camara and affiliates) has been targeted for the initial systematics and diversity studies. Originating in the Americas, Lantana is now a serious weed of natural environments, pastures, and farmland throughout the tropics and sub-tropics. Heavy lantana infestations occur along almost the entire East coast of Australia and patchy outbreaks occur in the Northern Territory and Western Australia. Biological control is the only practical method of controlling this weed, yet although many (> 41 worldwide and 28 within Australia) biocontrol agents have been applied little success has been achieved. Research is needed to determine the origins and genetics of the many Lantana varieties that have been introduced to Australia so as to properly target biocontrol agent discovery efforts.

We are conducting research on Lantana with three overarching objectives:

The establishment of the identity, diversity and origins of the various forms established in this country.

The production of molecular and morphological based evaluations of species and genetic diversity to assess phylogenetic relationships and implications for selection of biocontrol agents.

An assessment of the amount of interpopulation/race genetic variation of this weed species within Australia and the processes that structure this variation.

The project is using the collection resources of the Australian National Herbarium and its partner agencies in the Taxonomy Research & Information Network (TRIN) together with those of weed management agencies. We maintain an active collaboration with entomologist Dr Michael Day of QLD Department of Primary Industries. We are employing a variety of molecular genetic techniques, including DNA sequencing, microsatellites and AFLPs, in order to identify genetic markers for analysis of the evolution and introduction history of lantana. We intend to adapt and employ these techniques for use in the study of the origins and relationships of the progenitors of other introductions to Australia and the implications for selection of biocontrol agents.

Visit the National Research & Information Network (TRIN) website for Lantana

2008 Report

A background literature review was conducted from which historical records of source populations of lantana were identified; and the extent of known lantana variability in Australia and its relation to species from the native range was assessed. A set of ~400 Lantana samples spanning the Australian distribution and multiple described species from across the native range was made available for study by our collaborator Michael Day and brought to CSIRO. Samples were assigned morphometric identifications by Roger Sanders from Florida. A genetic marker development program was designed and implemented based on the accumulated information and tissue samples, and from pilot sequence data.

In the laboratory a staff member was recruited to the team to provide technical support. A method for extracting DNA from archival Lantana material was developed and PCR protocols were optimised. Then a set of 12 diverse Lantana tissue samples that encompassed several species and varieties from populations across the Australian and native ranges was characterised for 12 chloroplast loci and one nuclear locus in order to identify potentially useful genetic markers. Analysis of these results found unexpectedly limited diversity within Lantana at that level. Additional samples from a further ten described species are currently being characterised for one chloroplast and one nuclear locus to test the generality of the result. The preliminary findings are consistent with the original survey, and if confirmed then these findings will result in a paradigm shift in our understanding of the source of diversity within Lantana.

The work undertaken has been highly effective. Our initial strategy rapidly placed an upper bound on the phylogenetic diversity within weedy Lantana in Australia. We now know that phenotypic diversity in Lantana greatly exceeds the diversity at loci commonly used for measuring species relationships. This suggests that functional diversity in weedy Lantana is at the sub-specific level. This work has been conveyed to biocontrol practitioners and to other taxonomists working on Lantana. We are in the planning phase of an AFLP project that will allow us to describe this diversity.